Risk Mitigation for Dynamic State Estimation Against Cyber Attacks and Unknown Inputs
This work addresses cybersecurity risks in power grids, which is critical for grid operators and stability, but it appears incremental as it builds on existing dynamic state estimation methods.
The paper tackles the problem of cyber attacks and unknown inputs in power grids by proposing a risk mitigation strategy based on dynamic state estimation, which uses PMU measurements and incomplete system models to eliminate threats and ensure observability, with validation through case studies.
Phasor measurement units (PMUs) can be effectively utilized for the monitoring and control of the power grid. As the cyber-world becomes increasingly embedded into power grids, the risks of this inevitable evolution become serious. In this paper, we present a risk mitigation strategy, based on dynamic state estimation, to eliminate threat levels from the grid's unknown inputs and potential cyber-attacks. The strategy requires (a) the potentially incomplete knowledge of power system models and parameters and (b) real-time PMU measurements. First, we utilize a dynamic state estimator for higher order depictions of power system dynamics for simultaneous state and unknown inputs estimation. Second, estimates of cyber-attacks are obtained through an attack detection algorithm. Third, the estimation and detection components are seamlessly utilized in an optimization framework to determine the most impacted PMU measurements. Finally, a risk mitigation strategy is proposed to guarantee the elimination of threats from attacks, ensuring the observability of the power system through available, safe measurements. Case studies are included to validate the proposed approach. Insightful suggestions, extensions, and open problems are also posed.